1. Field of the Invention
The present invention relates to a coaxial connector mounted on a circuit board and, especially, to a coaxial connector having a switch for switching a high-frequency signal circuit.
2. Description of the Related Art
A coaxial connector having a switch is widely used for testing a high-frequency circuit in a portable communication equipment, such as a portable telephone. Such a coaxial connector is described in Japanese Patent Application Kokai Nos. 10-208817 and 10-3968.
FIGS. 11 and 12 show a coaxial connector having a switch disclosed in JP 10-208817. The coaxial connector comprises an insulative housing 2 having an insertion hole 3, an outer conductor 3 provided outside the insulative housing 2, and a pair of fixed and movable terminals 5 and 6 provided in a space 4 communicating with the insertion hole 1. The movable terminal 6 comprises a zigzag portion 7 and a substantially U-shaped contact portion 8. As shown in FIG. 11, when a central conductor 9 of a probe is not plugged into the insertion hole 1, the contact portion 8 of the movable terminal 6 is pressed against the fixed terminal 5 by the elastic force of the zigzag portion 7 so that the fixed and movable terminals 5 and 6 are electrically connected. However, as shown in FIG. 12, when the central conductor 9 of the probe is plugged into the insertion hole 1, the contact portion 8 of the movable terminal 6 flexes outwardly (downwardly in the drawing) to separate from the fixed terminal 5 so that the fixed and movable terminals 5 and 6 are electrically disconnected.
FIGS. 13 and 14 show a coaxial connector having a switch disclosed in JP 10-3968. The coaxial connector comprises an insulative housing 12 having a cavity 11, an outer conductor 13 provided outside the insulative housing 12, a pair of fixed and movable terminals 14 and 15 provided in the cavity 11, and an elastic member 15 provided under the movable terminal 16. As shown in FIG. 13, when a coaxial plug 17 is not inserted into the cavity 11, the movable terminal 15 is pressed against the fixed terminal 14 by the elastic forces of the movable terminal 15 itself and the elastic member 16 so that the fixed and movable terminals 14 and 15 are electrically connected. However, as shown in FIG. 14, when a central conductor 18 of the plug 17 is inserted into the cavity 11, the movable terminal 15 is pressed down by the central conductor 18 to elastically deform so that the fixed and movable terminals 14 and 15 are electrically disconnected.
However, the coaxial connector according to JP 10-208817 obtains a desired elastic force by providing the zigzag portion 7, and, therefore, the transmission line is made long so that the impedance is mismatched, thus making it difficult to improve the electrical characteristics. In addition, since the movable terminal 6 has a complicated shape, it is difficult to miniature the product and the manufacturing process requires a long period of time.
The coaxial connector according to JP 10-3968 has the problem that the stress is concentrated only on a fixed portion 19 of the movable terminal 15 during the flexure and deformation of the movable terminal 15, and, therefore, it is difficult to obtain a desired elastic force only by the movable terminal 15. Accordingly, the elastic member 16 is separately provided so that the number of parts is increased, the assembly work is difficult, and it is difficult to minimize the size of the product. In addition, electric current sometimes flows in the elastic member 16, which provides adverse effects on the high-frequency characteristics
Accordingly, it is an object of the present invention to provide a coaxial connector with a switch, which makes not only the manufacturing work easy but also the product small, and has the improved high-frequency characteristics.
According to an aspect of the invention, a coaxial connector with a switch mounted on a board comprises an insulative housing having an opening for receiving a central conductor of a coaxial plug from upside, an outer conductor provided outside the insulative housing and engaging with an outer conductor of the coaxial plug such that the plug is attached to or detached from the coaxial connector, a fixed terminal provided under the opening and having a contact portion, and a movable terminal provided under the opening and having a fixed portion fixed to the insulative housing and a cantilevered flexible portion extending from the fixed portion and contacting with the contact portion of the fixed terminal. When the central conductor of the coaxial plug is plugged into the opening of the insulative housing, the central conductor of the coaxial plug abuts against the flexible portion so that the flexible portion separates from the contact portion of the fixed terminal to switch a signal circuit. The flexible portion has at least one cut-off portion at a position located on a side of the fixed portion with respect to an abutting position with the central conductor of the coaxial plug.
The flexible portion, preferably, comprises side faces between which the distance increases from a vicinity of the abutting position toward the fixed portion of the movable terminal and the cut-off portion has a shape formed along the side faces. The cut-off portion, preferably, has a substantially triangular shape.
Alternatively, the side faces are curved from the vicinity of the abutting position toward the fixed portion of the movable terminal in a concave form.
According to another aspect of the invention, a coaxial connector with a switch mounted on a board comprises an insulative housing having an opening for receiving a central conductor of a coaxial plug from upside, an outer conductor provided outside the insulative housing and engaging with an outer conductor of the coaxial plug such that the plug is attached to or detached from the coaxial connector, a fixed terminal provided under the opening and having a contact portion, and a movable terminal provided under the opening and having a fixed portion fixed to the insulative housing and a cantilevered flexible portion extending from the fixed portion and contacting with the contact portion of the fixed terminal. When the central conductor of the coaxial plug is plugged into the opening of the insulative housing, the central conductor of the coaxial plug abuts against the flexible portion so that the flexible portion separates from the contact portion of the fixed terminal to switch a signal circuit. The flexible portion has side faces curved from a vicinity of an abutting position with the central conductor of the coaxial plug toward the fixed portion of the movable terminal in a concave form.
It is preferable that each of the side faces of the flexible portion is formed by a quarter circular arc having a diameter of substantially xc2xd to 2 times of a difference between a width of the flexible portion at the vicinity of the abutting position of the movable terminal and a width of the fixed portion of the movable terminal.
According to a still another aspect of the invention, a coaxial connector with a switch mounted on a board comprises an insulative housing having an opening for receiving a central conductor of a coaxial plug from upside, an outer conductor provided outside the insulative housing and engaging with an outer conductor of the coaxial plug such that the plug is attached to or detached from the coaxial connector, a fixed terminal provided under the opening and having a contact portion and a fixed portion, and a movable terminal provided under the opening and having a fixed portion fixed to the insulative housing and a cantilevered flexible portion extending from the fixed portion and contacting with the contact portion of the fixed terminal. The fixed portions of the fixed and movable terminals have substantially same width which is greater than a width of the flexible portion of the movable terminal, and at least one of the fixed and movable terminals comprises an arm portion to cover a space on both sides of the flexible portion.
With the above structure, the stress on the movable terminal during the flexure and deformation of the movable terminal is widely distributed and reduced, and, therefore, the durability of the movable terminal is increased.